The present invention relates to a heating, ventilation, and air conditioning (HVAC) unit or system to be installed in a vehicle.
Truck drivers that move goods across the country may be required to pull over at various times along their journey so as to rest so that they do not become too fatigued. Common places for truck drivers to rest include rest stops, toll plazas, and the like. However, these locations usually do not have any accommodations for the drivers, and as a result they usually remain inside the cab of the truck inside a sleeping compartment. To provide the driver with maximum comfort, the sleeping compartment should be temperature controlled so that the environment in the truck is conducive for the driver to get the rest he or she needs.
Currently, trucks tend to use engine-belt driven compressors for the air conditioning system to circulate and pump refrigerant throughout the vehicle to cool the driving compartments. In addition, an engine-belt driven pump can circulate engine waste heat throughout the driving compartments when heating is required. Unfortunately, these systems have the drawback of not being able to operate when the engine is turned off. As a result, the driver has the choice of either keeping the engine running (which requires additional fuel) so as to run the temperature control system or turning the engine off and not using the air conditioning or heating systems (which can make the driver uncomfortable).
In view of the above, there is a need to provide an HVAC system which can provide temperature control when the engine is turned off and can provide the necessary power to the heating and cooling system. One option is to use the battery of the truck to power the HVAC system. This option has the drawback that the HVAC system may have to be turned off at a certain point so that the battery does not drain to the point that the vehicle cannot be started. Thus, there is a need to provide a battery management system that will maximize the amount of time that the HVAC system can run when the engine is turned off yet does not drain the vehicle battery such that the vehicle cannot start.
Another drawback is that heaters used in the heating system often run on diesel fuel. As previously mentioned, engine-belt driven pumps can circulate engine waste heat throughout the driving compartments for heating purposes but these pumps require fuel. Alternatively, a dedicated burner can be used which pulls fuel from the tank (when the engine is not running) and burns it to heat air directly or through circulated water. Thus, there is a need to provide a heating system in the HVAC system which is capable of running while the engine is turned off such that no diesel fuel is being expended.
Another drawback is that the replacement of an HVAC system can result in a laborious and costly installation process. For example, the replacement of an HVAC system might mean the replacement of existing and fully functional equipment that is already on the vehicle, such as replacing the evaporator, circulation fans, or ducting. Thus, there is a need to provide an HVAC system that can be easily installed and does not necessarily involve the replacement of all the existing components of a vehicle's HVAC system.